1. Field of the Invention
The invention concerns a drive device for several units of a machine.
2. Description of the Related Art
From DE 44 32 308 C2 is known a drive device for auxiliary units such as tailstock or back rest of a CNC lathe, in which, in addition to the main feed shaft of controlled position for longitudinal and cross slides, an additional feed shaft of controlled position designed as a screw spindle is arranged parallel to the main feed shaft. The feed shaft designed as a screw spindle is driven by a further drive motor, and a nut with anti-twist means and a coupling device for entraining the auxiliary units is arranged on the screw spindle. The nut with coupling device is in each case moved under the auxiliary unit to be displaced, and a driver bolt present in the auxiliary unit is extended and latched in the coupling device. Conversely, entrainment of the auxiliary unit is interrupted by pulling the driver bolt.
This known drive device has the drawback that it is always only one unit that can be positioned or entrained, while the others remain stationary during this time.
From U.S. Pat. No. 4,977,788 is provided a drive device for several units of a machine, which comprises a sliding inertia drive. The latter is provided on the spindle circumference with longitudinal grooves in which locking pawls can be latched for positioning the units stepwise.
It is therefore the object of the invention to provide a drive device for several units of a machine, with which the units can be positioned simultaneously or independently of each other individually or in groups.
This object is achieved according to the invention by the characteristics of the main claim.
Due to the fact that several inertia drive nuts allocated to the units are provided on the inertia drive spindle and the inertia drive nut of each unit to be positioned is mounted rotatably but axially non-displaceably in a housing rigidly connected to the unit, wherein, by a brake which produces a force-locking connection, for the unit to be actuated at any given time an operative connection to the spindle is made, whereas for the unit which is to remain at rest during this time the operative connection is released and a force-locking connection of the nut to the spindle is made instead, which achieves rotation of the nut with the spindle and so prevents uncontrolled twisting of the nut, the units mounted on one spindle can be positioned independently and/or simultaneously.
Due to the measures provided in the subsidiary claims, advantageous developments and improvements are possible.